7-year-old Howard Kakita was standing on the roof of his grandparents and was enjoying watching the smoke from the approaching B-29 when the air siren sounded.

It was on a clear, sunny, sunny morning on August 6, 1945 in Hiroshima, Japan.

Born in California, the two Kakita brothers are American citizens, just like their parents.

More than 10 servicemen, crew members of the US plane, shot down in the final days of the war and captured by Japanese forces as prisoners of war, died after the bomb exploded.

Many of them are children from Hawaii and the US West Coast, returning to Japan many years before the war to visit relatives or learn about their origins.

Although there is no exact estimate of the number of Americans being hibakusha (Japanese word for survivors of the atomic bombing), the Japanese government is committed to taking care of their lives for the rest of their lives and often sends them

For decades, these teams of doctors have met many survivors of the bombing, blood sampling, checking for vital signs, x-rays and asking them about what to suffer, like the impact.

Forty Americans took part in such a routine health check last November, including Howard Kakita, a retired computer engineer.

Yaozo, Howard's grandfather, is a farmer and the first family member to come to America.

However, contrary to expectations, Mr. Yaozo faced many difficult years in the US because of being banned from naturalization and the wave of protest against the Japanese.

In 1906, he again went to America with his newlywed wife.

But the life of Mr. Yaozo's family is not easy as US law prohibits Japanese immigrants from owning or renting long-term land.

Earlier that year, second son Frank and his wife Tomiko took their two children to Hiroshima to meet grandfather Yaozo and decided to stay in the city to wait for the third child.

But in 1941, the Pearl Harbor battle broke out and everything changed.

Only later did Howard realize that his survival after the atomic bomb exploded in Hiroshima was a miracle.

Howard fainted under the rubble and when he woke up, the boy had to find his own way out.

"It reminded me of blood and corpses," he said.

When they returned to the residential area, the air was filled with the stench.

While on the other side of the Pacific, Howard's parents thought both of their children were dead.

The war ended after that, but did not help them to reunite.

In March of the following year, Kenny and Howard were taken aboard a ship to San Francisco, a strange land with unfamiliar language, a place whose parents they did not remember clearly, and two siblings they had never met.

Their family lives in a three-story apartment.

It took many years later, Howard was able to get rid of obsession and talk about Hiroshima bombing, while Kenny still can not share the past.

"I feel responsible," Howard, now 82, explained the reason for sharing his story.

Last fall, he spoke with hundreds of history students at the University of California at Los Angeles (UCLA), the school he attended.

Howard's story also includes the process of him gradually getting rid of the ghosts of the past, to start life and pursue his education.

In 1960, after graduating, Howard met Irene Doiwchi, who would later become his wife.

However, that did not discourage Irene.

Howard no longer seems obsessed with the past for a long time afterwards.

"Is it because of me," Howard wondered, fearing the effects of radiation, though his two daughters and four grandchildren had no problems.

The Kakitas family has long forgiven the past, as the Japanese and American have tried to do.

"We will only live 5-7 more years," he said.

Last September, Howard and Irene visited Hiroshima and the peace memorial museum there.